Radio apparatus



P 16, 1952 G. 'c. LARSON 2,611,111

RADIO APPARATUS Filed Ejebl s, 1950 From Output Derec1orl2. as

Power Lines TolO,|lundl2.

INVENTOR WITNESSES:

Gilbert C, Larson.

Patented Sept. 16, 1952 UNITED STATES PATENT orries Gilbert C. Larson, Sunbury, Pa.,-assignor to Westinghouse Electric-Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 3, 1950, Serial No. 142,287 .8 Claims. (01. 315-95) This invention relates to electronic apparatus, and it relates more particularly to radio receivers of the type which are adapted to be operated from batteries, or from alternating or directcurrent power lines.

A satisfactory type of portable radio receiver uses vacuum tubes having filaments, serving as cathodes, which areheated from the plate voltage supply circuit when the receiver is operating from power lines, and which are heated by batteries when power lines are not available. The output tubes used for battery operation have limited power-handling capacity, and it is customary to employ switching mechanism for substituting a more powerful output tube for the battery-operated output tube when the receiver is operated from power lines. .7

An object of this invention is to simplify-the circuit of a radio receiver using a battery-operated output tube when the receiver is operating frombatteries, and using a'higher capacity output tube when the receiver is operated from power lines.

. Another object of the invention is'to simplify the switching mechanism required for substitutfora battery-energized output tube.

The invention will now be described with refer ence to the drawing which is a circuit schematic illustrating a portable radio receiver embodying the invention.

The receiver illustrated has a conventional superheterodyne circuit comprising the oscillatormixer tube [0, the intermediate frequency amplifier tube H and the second detector tube 12. The tubes W, H, and I2 have the filamentary cathodes l3, l4, and'l5, respectively. The input and output circuits of these tubes are not illustrated since forming no part of this invention.

The battery-energized, audio output tube 16 has a filament I1 serving as its cathode, which is connected in series with the filaments l3, l4, and Hi, the A battery 21 and ground, when the'switch I9 is on the contact 20, and when the battery switch 22 is on the contact I8.

The output tube I6 has its plate 23' and its screen grid 24 connected to the opposite ends of the primary winding of the output transformer 25, the secondary winding of which is connected to the voice coil of the loud-speaker 26. The

suppressor grid 21 of the tube I6 is connected to its filament l1, and its control grid 28 is connected to the output circuit of the detector tube l2 as is conventional.

One side of the primary winding of the output transformer is connected to the switch 30 which is connected through the wiring 29, a pore tion only of which is shown, to the plates and the screen" grids of the tubes 10, II, and I2, and which, when the receiver is battery operated, is on thecontact 3!, which is connected to the positive terminal of the B" battery 32. The minus terminal of the battery 32 is connected to ground when the switch 22 is on the con-'- tact IS.

The series connection between the filament l5 of the tube 12 and the filament I! of the tube 16 is connected to the contact 33 of the switch 34. When the receiver is battery operated, the switch 34 is spaced from the contact 33.

The output tube 36 is apower output, tube having several times the power-handling capacity of the tube Hi. It has a filament 37 which draws the same current as the filaments of the tubes H), II, and I2 which, for example, may be milliamperes, and has a filament voltage of about 100 volts. Its filament 31, which serves as its cathode, is connected to the filament I1 of-the output tube [5, and its control grid 39, its screen grid 40, and its plate 4| are connected to the control grid 28, the screen grid 24 and the plate 23, respectively, of the output tube [6. Its suppressor grid 38 is connected to its filament 31.

The power line 42 is adapted to be connected through the switch and its contact 6| to the plate 43 of the rectifier tube 44 and to one side of its filament 45, the other side of which is connected to the power line 46 and'to ground. The indirectly heated cathode 41 of the rectifier tube 44 is connected through the series-connected filter resistors 48 and 49 to the contact 50 of the switch 30. The capacitors 51 are the usual filter capacitors.

One side of the filament 31 of the output tube 36 is connected to the junction point of the resistors 48 and 49, and its other side is connected to the switch 34.

The switches 60, 34, I9, 30, and 22 are interconnected by the linkage 35 so that they can be simultaneously adjusted for switching the receiver from battery operation to power line operation and vice versa. These switches can be ganged so as to be operated by a single control knob.

When the receiver is to be battery operated, the switches 60, 34, I9, 30, and 22 are moved from the positions shown by the drawing, to the left facing the drawing so that they touch the contacts 62, 63, 20, 3 l, and 18, respectively. The c ntacts 62 and 63 are not connected in the circuit. 1

This results in the switch 60 being spaced from,

the contact 6| thereby disconnecting the receiver from the power lines, and results in the switch 34 being spaced from the contact 33 therebydi's-. connecting the filament 3! of the output tube 36' from the filaments of the tubes l0, II, and [2.

It also results in the switch l9 touching the contact 20, thereby connecting the filaments of the. ,20

tubes [0, ll, l2 and I6 in series with the A" battery, 2] It also results in the switch 30 touchme he contact}! and connecting the primary of the output transformer 25 tothe posisuits" mi me switch 22 touching; the contact i8 i thereby completing the circuit for energizing ments of ,the tubes l3, H, [2, and- Iji from 36 is d'e'ener gized and the output tube; energizes the loud speaker 26. I l

h t er sicibl ret iiri rq 1 1ev witc s 41, d 22 a e aw kic-ihe ht cin hex aw nsi t t e onsfillustrated' thereby. This results in the t shes}? a a-39- l er m n c s an 1 i 9t v liuihere 1 disc n e t an fBjbatt eries from'the tubes, and results in the wine-summ th rc e wirh r necti ng the wiring 29. and the output transformer 25 to the filter resistor 49. It also resultsin the switch 34 moving against the contact 33, thereby connecting the filaments ltf, l4, and 150i the tubesflfl, H, and 1? respectively.; in;se ries with ing'connected to the junction point of theseriesconnected, filter resistors 48 and. 49, causes the filaments of th'etubes [0",] 1, l2, and 36 to be ,enere rapt 61,; thereby ener izing th rectifier tube 44 :frointhe power lines. At this time, the output tube 16 isde'enrgiaed since its filament circuit is open, and the output tube 36 energizes theloudspeaker 26; I

-:I-n.prior circuits in'which the filaments" ofthe tubesacorresponding" to thetubes If, and i2 wererene'rgized from the rectifier circuit, a voltage dropping or ballast resistor wasiused for reducing the; relatively high voltagefrom the rectifier so as to avoid burning out the filaments .of l the tubes.

In this inyention, the filamentof, the output tube 36'replaces sucha ballast resistor and eliminates its expense, This invention alsofprovides; im1- prgved efiiciency by utilizing the powerwhich is normally dissipated ma ballast, esistor for heatilig'i'ih filaments, Q i eh rppwerout ut tub tnnotne advantage or this invention is that although-alarge capacity output tube-is used when the receiver is operated frorn power lines, no more filament power is eonsumedjhanfis conj ld' re eiv rs usin at output 7 tubes when operated from power lines g Another advantage of this invention is that the switchingof the output tubesis accomplished mpl a dinex n iv lrq erminal of the B battery 32. It also -re-- A battery. At this time, the,- output tube thei filament iil ofthe output;tube36 which, be-- bycurrent.irorn thejrectifierftube 44., It'alsjof results inithe switch moving against the 'con-,

said rectifier circuit.

2. Electronic apparatus comprising a plurality f electron tubes having filaments connected in series, a battery, first and second output electron tubes having filaments, a rectifier circuit, and

1 switching means for connectin said first-mentioned filaments and the filament of one of said output tubes in series with said battery, or alternatively for connecting said first-mentionegifilamentsan'd the filamentkof the other of-said output tubes in series to said rectifier circuit.

eff'Electronic apparatus comprising a, plurality of electron tubes having filaments c o nnected in.

series, a battery, first and second output electron b s. ha g fi amen acti er c rc t. and switching means operable in one position to con nect said first-mentioned filaments and the file-:1

e t o one of s ou pu tubes in series with said batter and operable in anothercposition,

to connect said first mentioned filaments and the l filament of the other ofcsaid output tubes in series.

tosaid rectifier'circuit. w, 4. Electronic apparatuscomprising a plurality of electron tubes havingfilaments.connected'in series, first and second output electron tubeshaw ingfilaments and anodes, a filamentenergizing battery, an anode supply battery, a rectifier cir cuit,,and switching'means. for connecting-said first-mentioned filaments and the filamentoi saidfirst. output tube in series with said filament energizing battery and for connecting 'the anode ofi-isaidi first outputtube to said anode supply battery, .or alternatively for connecting said firstmentioned filaments and thefilament of 'said second output tube 'in series to said rectifier circuit, and fer connecting the anode'of said second output. tube to saidrectifier circuit.

5. Electronic apparatus comprising a pluralityof electron tubes havingfilamentsconnectedseries, first and second output electron tubes having filaments and anodes, a filament-energizing battery, an anode supply battery, a rectifier 'cire cuit, and interconnected switching means op-" erable in one positionforconnecting saidfirst-j mentioned filaments and the filamentof said first output tube inseries with said filament-energizing battery, and for connecting the anode: of'said'i first output tube to said anodesupply: batteryfi and operable in another position for'connect ing said first-mentioned filaments-and the "filament'of saidsecond output tubein-series-tcsaid rectifier circuit and for connecting the 'anode'of said second output tube to'said rectifier circuitfi 6.-'.- A radio' receiver comprisinga plurality of electron tubes having filaments connected in series, first and secondoutput electron tubes havingifilamenta having control grids and hav ing anodes','means connecting said' control grids together, an output transformer having a mary winding, means connecting said anodes to gether and to said winding, a mament-energize mg battery, an anode supply battryya rectifier circuit, and switchingmeans-for connecting said first-mentioned filaments and the filament of said first output tube in series with said filamentenergizing battery, and for connecting said winding to said anode supply battery, or alternatively for connecting said first-mentioned filaments and the filament of said second output tube in series to said rectifier circuit, and for connecting said winding to said rectifier circuit.

7. A radio receiver comprising a plurality of electron tubes having filaments connected in series, first and second output electron tubes having filaments, having control grids and having anodes, means connecting said grids together, an output transformer having a primary winding, means connecting said anodes together and to said winding, a filament-energizing battery, an anode supply battery, a rectifier circuit, and interconnected switching means operable in one position for connecting said first-mentioned filaments and the filament of said first output tube in series with said filament-energizing battery. and for connecting said winding to said anode supply battery, and operable in another position for connecting said first-mentioned filaments and the filament 01. said second output tube in series to said rectifier circuit, and for connecting said winding to said rectifier circuit.

8. A radio receiver comprising a plurality of electron tubes having filaments connected in series, first and second output electron tubes having filaments, having control grids and having anodes, means connecting said grids together, an output transformer having a primary winding, means connecting said anodes together and to said winding, a filament-energizing battery, an anode supply battery, a rectifier, a power line connection for said rectifier, and interconnected switching means operable in one position for connecting said first-mentioned filaments and the filament of said first output tube in series with said filament-energizing battery, and for connecting said winding to said anode supply battery, and operablein another position for connecting said connection to said rectifier, for connecting said first-mentioned filaments and the filament of said second output tube in series to said rectifier, and for connecting said winding to said rectifier.

GILBERT C. LARSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,220,051 Israel Oct. 29, 1940 2,222,196 Vilkomerson Nov. 19, 1940 2,269,989 Root Jan. 13, 1942 

